Radio 1 DJ Mary Anne Hobbs's one-off January show Dubstep Warz marked the emergence into the mainstream of a genre which has been fermenting in south London raves and pirate stations for much of this decade. Her follow-up compilation, a mixture of exclusives and recent dubstep anthems, continues her sterling work. Dubstep's sonic palette is one of cavernous bass twinned with skanking beats and the occasional sample. It is dark and murky, an instrumental reflection of gloomy London nights, but the dancefloor imperative of Digital Mystikz's Anti-War Dub or Burial's Versus is hard to resist. It is also intensely physical - the broad brushstrokes of bass that underpin the sampled police sirens and club chatter on Loefah's Mud VIP seem designed to make your entire body judder. Elsewhere, Manchester's Virus Syndicate crew are spectacular on Dead Man Walking, all rapid-fire distortion and frenetic MCing, while JME's playground flow lightens the mood briefly as he coolly dissects hand-to-mouth living on Pence. This is a superb introduction to some of the most thrilling, forward-thinking music in the UK today.